function deleteSpecific_Columns() {

const keep = [1, 3]; // columns G and M

const newSheet = SpreadsheetApp.getActiveSheet();

deleteColumns_(newSheet, keep);

}

function deleteColumns_(sheet, columnsToKeep) {

// version 1.0, written by --Hyde, 13 June 2022

// - see https://stackoverflow.com/q/72600890/13045193

const columnsToDelete = [];

for (let i = 1, maxColumns = sheet.getMaxColumns(); i <= maxColumns; i++) {

if (!columnsToKeep.some(columnNumber => i === columnNumber)) {

columnsToDelete.push(i);

}

}

const tuples = getRunLengths_(columnsToDelete).reverse();

tuples.forEach(([columnStart, numColumns]) => sheet.deleteColumns(columnStart, numColumns));

}

function getRunLengths_(numbers) {

// version 1.1, written by --Hyde, 31 May 2021

if (!numbers.length) {

return [];

}

return numbers.reduce((accumulator, value, index) => {

if (!index || value !== 1 + numbers[index - 1]) {

accumulator.push([value]);

}

const lastIndex = accumulator.length - 1;

accumulator[lastIndex][1] = (accumulator[lastIndex][1] || 0) + 1;

return accumulator;

}, []);

}